Anatomic structures which are frequently inflamed in this syndrome include the rotator cuff, subacromial bursa, and the biceps tendon. The rotator cuff is the tendinous part of four muscles which attach to the head of the humerus. These muscles help to control and coordinate movement of the shoulder joint. The subacromial bursa is a lubricating structure which lies above the rotator cuff and under the acromion (a bony projection of the shoulder blade). The tendon of a portion of the biceps muscle actually originates within the shoulder joint and passes through the rotator cuff on its way down the arm. One or all of these structures may be inflamed and act as a source of pain.
Often the joint between the acromion and the clavicle, more commonly known as the collarbone, is also involved. If this joint has developed arthritis, bone spurs may project downward toward the shoulder joint. The bone spurs, which are also called osteophytes, may crowd the underlying bursa and rotator cuff causing a mechanical source of irritation.

Relief from the symptoms of Impingement Syndrome can often be obtained with rest and anti-inflammatory medication. Physical therapy is often prescribed to aid in the control of inflammation, as well as, to improve motion and strength. If these measures fail to produce the desired effect, an injection of an anti-inflammatory steroid, such as Cortisone or a related medication, can bring about dramatic relief.

Only when symptoms persist or worsen despite use of these treatment methods is surgery considered. The surgical procedure usually recommended consists of removing the inflamed bursa and smoothing or reshaping the undersurface of the acromion. If indicated bone spurs and the end of the clavicle may also be removed. This surgery is usually done using the arthroscope and involves three of four small incisions about the shoulder. Using the arthroscope allows for inspection of the entire shoulder and treatment of associated problems within the joint.
A period of rehabilitation and physical therapy follows surgery. Most patients are able to resume all normal activities within a few weeks of their surgical procedure.